Display device with integrated touch screen and method for driving the same

ABSTRACT

Discussed are a display device with an integrated touch screen and a method of operating the same. The display device according to an embodiment includes a display panel including a plurality of pixel electrodes; a touch screen including m number of electrodes which are formed to overlap with the plurality of pixel electrodes, wherein m is a multiple of n, and n is an integer equal to or greater than two, and wherein the m electrodes are divided into n number of electrode groups; a touch driver configured to generate a touch scan signal and to supply the generated touch scan signal to a display driver; and the display driver configured to apply a common voltage or the touch scan signal to one or more of the m electrodes depending on a driving mode of the display device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application under 35 U.S.C. § 120 ofU.S. patent application Ser. No. 13/448,021 filed on Apr. 16, 2012,which claims the priority benefit of the Korean Patent Application No.10-2012-0016908 filed on Feb. 20, 2012, both of which is herebyincorporated by reference as if fully set forth herein.

BACKGROUND

Field of the Invention

The present invention relates to a display device, and moreparticularly, to a display device with an integrated touch screen and adriving method thereof.

Discussion of the Related Art

Touch screens are a type of input device that is included in imagedisplay devices such as Liquid Crystal Displays (LCDs), Field EmissionDisplays (FEDs), Plasma Display Panel (PDPs), ElectroluminescentDisplays (ELDs), and Electrophoretic Display (EPDs), and allows a userto input predetermined information by applying a pressure (i.e., bypressing or touching) to a touch sensor of a touch screen of the imagedisplay device while looking at the image display device.

Particularly, the demand of display devices with an integrated in-celltype touch screen, which include a plurality of built-in elementsconfiguring the touch screen for providing slim portable terminals suchas smart phones and tablet Personal Computers (PCs), is recentlyincreasing.

Hereinafter, a related art display device with an integrated touchscreen will be described with reference to FIG. 1.

FIG. 1 is a diagram illustrating a configuration of a related artdisplay device with an integrated touch screen, and more specificallyillustrates a configuration of a display device with an integratedself-capacitive touch screen having an in-cell type.

The related art display device with the integrated self-capacitive touchscreen having an in-cell type, as illustrated in FIG. 1, includes: apanel 10 with a built-in touch screen 11; a display driver IC (DD-IC) 20that is connected to an external system and controls a plurality of gatelines and data lines in the panel 10; a plurality of touch ICs (T-IC1and T-IC2) 31 and 32 that drive the touch screen 11 in the panel 10.

The panel 10 includes m number of electrodes 12, and m number of lines13 that are respectively extended from the m electrodes 12. Each of thetouch ICs 31 and 32 includes m number of touch IC channels respectivelycorresponding to the m lines 13, for self-capacitive touch sensing.

Since one touch IC channel generally corresponds a line connected to anelectrode in one-to-one correspondence relationship, as illustrated inFIG. 1, when the number of lines connected to an electrode is more thanthe number of channels that are capable of being accommodated by onetouch IC, a plurality of touch ICs are required to be used, causing theincrease in cost.

In the display device with the integrated touch screen of FIG. 1, eachof the electrodes 12 is built in the panel 10 and performs a touchfunction and a display function, and thus is used as a common electrodefor display driving when the display device is driven in a displaydriving mode, or is used as a touch electrode when the display device isdriven in a touch driving mode. The display driving mode is a displaymode for displaying images on the display device, and the touch drivingmode is a touch mode for detecting and processing a touch input to thedisplay device.

On the contrary, when the display device is driven in the displaydriving mode, a common voltage Vcom outputted from inside the displaydriver IC (DD-IC) 20 is applied to the electrodes 12 through the touchICs 31 and 32, in which case the touch ICs 31 and 32 need to accommodatea negative voltage when the common voltage Vcom is the negative voltage.

However, the related art touch ICs 31 and 32 cannot accommodate anegative voltage and thus, a special manufacturing process and designfor a touch IC that can accommodate the negative voltage are needed,which in turn increases the manufacturing cost of the touch ICs.

Moreover, when the related art touch sensitive display device is drivenin the display driving mode, a ground-level voltage instead of anegative voltage may be incidentally supplied to the electrode 12through the touch IC, thereby causing the degradation of image quality.

To provide a summary on the above-described limitations, the related artdisplay device with the integrated touch screen has at least thefollowing limitations.

First, as the number of touch IC channels matching the respective linesconnected to electrodes increases, the number of touch ICs increases,thereby causing the increase in cost for the display device.

Second, a touch IC is separately manufactured by modifying themanufacturing process and design thereof for applying a negative commonvoltage, thereby causing the increase in the manufacturing cost of thetouch IC.

Third, when the related art touch IC is applied to a display device, theground-level common voltage, instead of the desired negative commonvoltage, may be incidentally applied to the electrodes in the displaydriving mode, thereby causing the degradation of image quality.

SUMMARY

Accordingly, the present invention is directed to provide a displaydevice with an integrated touch screen that substantially obviates oneor more problems due to limitations and disadvantages of the relatedart.

An aspect of the present invention is directed to provide a displaydevice with an integrated touch screen, which applies a common voltageor a touch scan signal to a plurality of electrodes through a switchingunit that is connected to at least two or more electrode groups of aself-capacitive touch screen.

Another aspect of the present invention is directed to provide a displaydevice with an integrated touch screen, which enables the reduction inthe number of touch IC channels that connect a display driver IC and atouch IC by using only one touch IC.

Another aspect of the present invention is directed to provide a displaydevice with an integrated touch screen, which applies a common voltagedirectly from a display driver IC to an electrode without applying thecommon voltage to the electrode though a touch IC, thus preventing imagequality from being degraded.

Additional advantages and features of the invention will be set forth inpart in the description which follows and in part will become apparentto those having ordinary skill in the art upon examination of thefollowing or may be learned from practice of the invention. Theobjectives and other advantages of the invention may be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the invention, as embodied and broadly described herein, there isprovided according to an embodiment a display device with an integratedtouch screen including: a touch screen including m number of electrodeswhich are formed to respectively overlap with a plurality of pixelelectrodes in a pixel area of a panel, m being a multiple of n wherein nis an integer more than or equal to two; a display driver IC applying acommon voltage to the electrodes, or applying a touch scan signalsequentially to n number of groups into which the m electrodes aredivided, according to a driving mode of the panel; and a touch ICgenerating the touch scan signal to apply the touch scan signal to thedisplay driver IC.

When the driving mode is a display driving mode, each of the electrodesmay operate as a common electrode, or when the driving mode is a touchdriving mode, each of the electrodes may operate as a touch electrode.

The number of electrodes included in each of the groups may be m/nnumber. The n groups may be block type groups. The groups may be dividedand formed in a short side direction of the pixel area.

The display driver IC may include: a common voltage generator generatingthe common voltage; a sync signal generator generating a sync signalindicating the driving mode; a switching control signal generatorgenerating a control signal which allows the electrodes to besimultaneously connected to the common voltage generator or allows theelectrodes to be sequentially connected to the touch IC for each group,according to the sync signal; and a switching unit operating accordingto the sync signal and the control signal.

The switching unit may include a plurality of first switching units anda plurality of second switching units, the first switching units beingconnected to the common voltage generator and the touch IC, and thesecond switching units being connected to the respective first switchingunits and one electrode for each group. When the sync signal is a firstsync signal indicating the display driving mode, the first switchingunits may connect the common voltage generator to the second switchingunits, or when the sync signal is a second sync signal indicating thetouch driving mode, the first switching units may connect the touch ICto the second switching units. When the control signal is a firstcontrol signal conforming to the first sync signal, the second switchingunits may connect the respective electrodes to the first switchingunits, or when the control signal is a second control signal conformingto the second sync signal, the second switching units may sequentiallyconnect the respective electrodes to the first switching units for eachgroup.

The second control signal may include n number of group selectionsignals which allow the first switching units to be respectivelyconnected to the electrodes for each group.

Each of the second switching units may include a plurality of CMOStransistors, and control respective gates of the CMOS transistors tosimultaneously connect the first switching units and the groups orsequentially connect the first switching units and the groups for eachgroup. The number of first switching units may be m/n number.

In another aspect of the present invention, there is provided a drivingmethod of a display device with an integrated touch screen, whichincludes: a touch screen including m number of electrodes in a pixelarea of a panel (where m is a multiple of n and n is an integer morethan or equal to two); a display driver IC applying a common voltage ora touch scan signal to the electrodes; and a touch IC generating thetouch scan signal to apply the touch scan signal to the display driverIC, the method including: applying the common voltage to the electrodeswhen a driving mode of the panel is a display driving mode; andsequentially applying the touch scan signal to n number of groups intowhich the electrodes are divided, when the driving mode of the panel isa touch driving mode.

The number of electrodes included in each of the groups may be m/nnumber. The n groups may be block type groups. The groups may be dividedand formed in a short side direction of the pixel area.

The applying of the common voltage may include: generating the commonvoltage; generating a first sync signal according to the display drivingmode, and generating a first control signal according to the first syncsignal; switching a first switching unit to output the common voltageaccording to the first sync signal; and switching a second switchingunit to simultaneously apply the common voltage, outputted from thefirst switching unit, to the electrodes according to the first controlsignal.

The applying of the touch scan signal may include: generating the touchscan signal; generating a second sync signal according to the touchdriving mode, and generating a second control signal according to thesecond sync signal; switching a first switching unit to output the touchscan signal according to the second sync signal; and switching a secondswitching unit to sequentially apply the touch scan signal, outputtedfrom the first switching unit, to the n groups according to the secondcontrol signal.

According to an embodiment, the present invention provides a displaydevice with integrated touch screen, including: a display panelincluding a plurality of pixel electrodes; a touch screen including mnumber of electrodes which are formed to overlap with the plurality ofpixel electrodes, wherein m is a multiple of n, and n is an integerequal to or greater than two, and wherein the m electrodes are dividedinto n number of electrode groups; a touch driver configured to generatea touch scan signal and to supply the generated touch scan signal to adisplay driver; and the display driver configured to apply a commonvoltage or the touch scan signal to one or more of the m electrodesdepending on a driving mode of the display device.

According to an embodiment, the present invention provides a method ofoperating a display device, the display device including a display panelincluding a plurality of pixel electrodes and a touch screen including mnumber of electrodes which are formed to overlap with the plurality ofpixel electrodes, wherein m is a multiple of n, and n is an integerequal to or greater than two, the display device further including atouch driver and a display driver, the method including: dividing the melectrodes into n number of electrode groups; generating, by the touchdriver, a touch scan signal; and applying, by the display driver, acommon voltage or the generated touch scan signal to one or more of them electrodes depending on a driving mode of the display device, whereinwhen the generated touch scan signal is applied to the one or more ofthe m electrodes, the touch scan signal is selectively applied to eachof the electrode groups.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiments of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a diagram illustrating a configuration of a related artdisplay device with an integrated touch screen;

FIG. 2 is a diagram illustrating a configuration of a display devicewith an integrated touch screen according to an embodiment of thepresent invention;

FIG. 3A is a diagram illustrating a detailed configuration of each offirst and second switching units in FIG. 2;

FIG. 3B is a diagram for describing an operation of each of the firstand second switching units in FIG. 3A;

FIG. 4 is a diagram showing a first embodiment of an electrode divisionmethod in a display device with integrated touch screen according to anembodiment of the present invention;

FIGS. 5A to 5D are diagrams respectively showing an example ofexperiment data of touch sensitivity according to the method of FIG. 4;

FIG. 6 is a diagram showing a second embodiment of an electrode divisionmethod in the display device with integrated touch screen according toan embodiment of the present invention; and

FIG. 7 is a diagram showing a third embodiment of an electrode divisionmethod in the display device with integrated touch screen according toan embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the exemplary embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings.

In a display device with an integrated touch screen according to anembodiment of the present invention, a plurality of electrodes aredivided into n number of groups, and a touch scan signal is sequentiallyapplied to the n groups. However, for convenience of a description, thebelow description will be made on a method where the electrodes aredivided into two groups (i.e., n=2). However, the present invention isnot limited to the method where the electrodes are divided into the twogroups, and the electrodes may be divided into three or more groups.

FIG. 2 is a diagram illustrating a configuration of a display devicewith an integrated touch screen according to an embodiment of thepresent invention.

The display device with the integrated touch screen according to anembodiment of the present invention, as illustrated in FIG. 2, includes:a touch screen 111 that includes m number of electrodes 112 (where m isa multiple of n, and n is an integer more than or equal to two) whichare formed to respectively overlap with a plurality of pixel electrodesin a pixel area of a display panel 110; a display driver IC 120 thatapplies a common voltage Vcom to the electrodes 112 or sequentiallyapplies a touch scan signal to the electrodes of each of two groups 114into which the m electrodes 112 are divided, according to a driving modeof the panel 110; and a touch IC 130 that generates the touch scansignal and applies the touch scan signal to the display driver IC 120.

The touch screen 111 detects a touch point of a user. Particularly, thetouch screen 111 applied to the present embodiment is an in-cell typetouch screen using a self-capacitive type, and a touch screen area isthe same area as a pixel array area. The self-capacitive touch screenincludes the m electrodes 112 and the same m number of lines 113, in thepanel 110.

Herein, the panel 110 may be configured in a structure where a liquidcrystal layer is formed between two substrates. In this case, a lowersubstrate of the panel 110 can include: a plurality of data linesdisposed in parallel to each other; a plurality of gate lines that crossthe data lines and are disposed in parallel to each other; a pluralityof Thin Film Transistors (TFTs) that are respectively formed in aplurality of intersection areas between the data lines and the gatelines; a plurality of pixel electrodes that respectively charge datavoltages into the plurality of pixels; an electrode (also referred to asa common electrode) that drives liquid crystal cells injected into theliquid crystal layer, together with the operation of the pixelelectrodes. The pixels are arranged in a matrix type corresponding tothe above-described intersection structure between the date lines andthe gate lines.

The m electrodes 112 are formed to overlap with the plurality of pixelelectrodes, in the pixel array area of the panel 110. For instance, them electrodes are not formed in each pixel but are formed in an areaoverlapping with a plurality of pixels. That is, the m electrodes 112are preferably disposed over the area where the pixel electrodes aredisposed. The m electrodes 112 may be disposed substantially through thetouch screen 111 so that a touch input thereto may be accuratelydetected.

When the driving mode of the panel 110 is a display driving mode, eachof the electrodes 112 operates as a common electrode that drives liquidcrystal cells together with the operation of the pixel electrode(s)formed in corresponding pixel(s). When the driving mode of the panel 110is a touch driving mode, each electrode 112 operates as a touchelectrode that detects a touch point/input by using the touch scansignal applied from the touch IC 130.

For example, as illustrated in FIG. 2, the m electrodes 112 may beformed to be divided into two groups 114, and formed in a block typegroup 114 but the group can be in a different shape. Each of the groups114 may be formed in a touch screen 111 area, and the number ofelectrodes included in each group 114 is m/2. In FIG. 2, the number ofelectrodes in each of two groups into which the electrodes 112 aredivided is m/2, but when the electrodes 112 are divided into n number ofgroups, the number of electrodes in each of the n groups is m/n, where mand n are positive integers and preferably m is a multiple of n toprovide an even division.

The m lines 113 connect the m electrodes 112 to the display driver IC120, respectively. Therefore, the common voltage and the touch scansignal that are outputted from the display driver IC 120 are applied tothe electrodes 112 through the respective lines 113.

When the driving mode of the panel 110 is in the display driving mode,the display driver IC 120 applies the common voltage to the electrodes112, and when the driving mode of the panel 110 is in the touch drivingmode, the display driver IC 120 sequentially applies the touch scansignal to the electrodes of each of the two groups into which theelectrodes 112 are divided. Embodiments of a group division methodaccording to the present invention will be described below in detail.

The display driver IC 120 drives the data lines and gate lines that areformed in the panel 110, and drives each of the m electrodes 112 as acommon electrode or a touch electrode. For this end, the display driverIC 120 may include a common voltage generator 121, a sync signalgenerator 122, a switching control signal generator 123, and a switchingunit 124.

The common voltage generator 121 generates a common voltage Vcom andapplies the common voltage Vcom to the switching unit 124. Specifically,when the driving mode of the panel 110 is in the display driving mode,the common voltage generator 121 generates the common voltage Vcom whichis then applied to the m electrodes 112 for image output, and appliesthe common voltage Vcom to the switching unit 124.

The sync signal generator 122 generates a sync signal indicating thedriving mode of the panel 110. For example, as illustrated in FIG. 2,when the driving mode of the panel 110 is in the display driving mode,the sync signal generator 122 generates a first sync signal “0” thatallows the common voltage Vcom of the common voltage generator 121 to beapplied to the electrodes 112 through the switching unit 124. When thedriving mode of the panel 110 is in the touch driving mode, the syncsignal generator 122 generates a second sync signal “1” that allows thetouch scan signal of the touch IC 130 to be applied to the electrodes112.

The switching control signal generator 123 generates a control signalthat allows the electrodes 112 to be simultaneously connected to thecommon voltage generator 121 or a control signal that allows theelectrodes 112 to be sequentially connected to the touch IC 130 for eachgroup, according to the sync signal of the sync signal generator 122.For example, as illustrated in FIG. 2, when the sync signal of the syncsignal generator 123 is the first sync signal “0”, the switching controlsignal generator 123 generates a first control signal “00” that allowsthe common voltage (received from the common voltage generator 121) tobe simultaneously applied to the m electrodes 112. When the sync signalof the sync signal generator 123 is the second sync signal “1”, theswitching control signal generator 123 generates a second control signal“01” or “10” that allows the touch scan signal (received from the touchIC 130) to be sequentially applied to the two electrode groups 114. Thesecond control signal may be generated in plurality, according to thenumber of groups that are connected to the switching unit 124. In otherwords, in this example, the second control signal denotes two groupselection signals (“01” and “10”) that allow the switching unit 124 tobe connected to the electrodes 112 by two groups (CH1 and CH2). However,the electrodes 112 may be divided into two or more groups. In suchcases, when there are n number of groups (n being greater than or equal2), the second control signal corresponding to n number of groupselection signals that are respectively and selectively applied to the ngroups is generated. For instance, if there are 3 electrode groups 114,then the group selection signals of the second control signal may be,e.g., “001”, “010” and “011” which are used to respectively control thethree different electrode groups via the channel outputs CH1, CH2 andCH3 of each of the second switching units 126. The switching unit 124may be configured with a plurality of first switching units 125 and aplurality of second switching units 126. Each of the second switchingunits 126 includes channels CH1 and CH2. The switching unit 124 operatesaccording to the sync signal of the sync signal generator 122 and thecontrol signal of the switching control signal generator 123.

For example, as illustrated in FIG. 2, when the sync signal of the syncsignal generator 122 is the first sync signal “0” and the control signalof the switching control signal generator 123 is the first controlsignal “00”, the common voltage Vcom generated by the common voltagegenerator 121 is applied to all the electrodes 122. When the sync signalof the sync signal generator 122 is the second sync signal “1” and thecontrol signal of the switching control signal generator 123 is thesecond control signal “01” or “10”, the touch scan signal generated bythe touch IC 130 is applied to the m electrodes 112.

More specifically, when the second control signal of the switchingcontrol signal generator 123 is the second control signal “01”, thetouch scan signal from the touch IC 130 is applied to the electrodes ofone of the groups 114 through the channel CH1 of each of the secondswitching units 126. On the other hand, when the second control signalof the switching control signal generator 123 is the second controlsignal “10”, the touch scan signal is applied to the electrodes of theother one of the groups 114 through the channel CH2 of each of thesecond switching units 126.

The detailed configurations and operations of the first switching units125 and second switching units 126 of the switching unit 124 will now bedescribed in detail with reference to FIGS. 2, 3A and 3B according to anembodiment of the present invention.

FIG. 3A is a diagram illustrating a detailed configuration of each ofthe first and second switching units in FIG. 2. FIG. 3B is a diagram fordescribing an operation of each of the first and second switching unitsin FIG. 3A.

The first switching unit 125 may be configured with a 2:1 multiplexer.For example, as illustrated in FIG. 3A, the first switching unit 125 maybe configured with transistors TR1 and TR2. The transistor TR1 may beconnected to the common voltage generator 121 and the second switchingunit 126, and the transistor TR2 may be connected to the touch IC 130and the second switching unit 126. Herein, each of the transistors TR1and TR2 may be a CMOS transistor.

When the sync signal is the first sync signal “0” indicating the displaydriving mode, the first switching unit 125 connects the common voltagegenerator 121 to the second switching unit 126. When the sync signal isthe second sync signal “1” indicating the touch driving mode, the firstswitching unit 125 connects the touch IC 130 to the second switchingunit 126.

For example, when the sync signal of the sync signal generator 122 isthe first sync signal “0”, the transistor TR1 of the first switchingunit 125 is turned on and simultaneously the transistor TR2 is turnedoff, and thus, the common voltage generator 121 and the second switchingunit 126 are connected to each other through the transistor TR1 of thefirst switching unit 125, whereupon the common voltage Vcom generated bythe common voltage generator 121 is delivered to the second switchingunit 126. When the sync signal of the sync signal generator 122 is thesecond sync signal “1”, the transistor TR2 of the first switching unit125 is turned on and simultaneously the transistor TR1 is turned off,and thus, the touch IC 130 and the second switching unit 126 areconnected to each other through the transistor TR2 of the firstswitching unit 125, whereupon the touch scan signal generated by thetouch IC 130 is delivered to the second switching unit 126.

The second switching unit 126 is a signal selector that has one inputchannel and a plurality of output channels CH1 and CH2. The secondswitching unit 126 simultaneously or sequentially outputs a signal,supplied from the first switching unit 125, through the output channelsCH1 and CH2. For example, as illustrated in FIG. 3A, the secondswitching unit 126 may be configured with transistors TR3 and TR4, whichare connected to the first switching unit 125 and correspondingelectrodes 112 through the lines 113. Herein, each of the transistorsTR3 and TR4 may be a CMOS transistor.

The second switching unit 126 is connected only to the first switchingunit 125 and one electrode for each group. When the control signalapplied to the second switching unit 126 is the first control signalconforming to the first sync signal (display mode), the second switchingunit 126 connects the first switching unit 125 to all the electrodes112. When the control signal is the second control signal conforming tothe second sync signal (touch mode), the second switching unit 126sequentially connects the first switching unit 125 to a plurality ofelectrodes for each group 114.

For example, when the control signal of the switching control signalgenerator 123 is the first control signal “00” conforming to the firstsync signal “0” of the sync signal generator 122, the transistors TR3and TR4 of the second switching unit 126 are simultaneously turned on,and thus, the first switching unit 125 and all the electrodes 112 areconnected to each other through the channels CH1 and CH2 of therespective transistors TR3 and TR4 in the second switching unit 126,whereupon the common voltage Vcom delivered from the first switchingunit 125 is applied to all the electrodes 112 including both groups 114simultaneously.

When the control signal of the switching control signal generator 123 isthe second control signal “01” conforming to the second sync signal “1”of the sync signal generator 122, the transistor TR3 of the secondswitching unit 126 is turned on and simultaneously the transistor TR4 isturned off, and thus, the first switching unit 125 and the electrodes ofany one of the groups 114 are connected to each other through thechannel CH1 of the transistor TR3 of the second switching unit 126,whereupon the touch scan signal delivered from the first switching unit125 is applied to all the electrodes of that one group among the groups114.

When the control signal of the switching control signal generator 123 isthe second control signal “10” conforming to the second sync signal “1”of the sync signal generator 122, the transistor TR4 of the secondswitching unit 126 is turned on and simultaneously the transistor TR3 isturned off, and thus, the first switching unit 125 and the electrodes ofthe other of the groups 114 are connected to each other through thechannel CH2 of the transistor TR4 of the second switching unit 126,whereupon the touch scan signal delivered from the first switching unit125 is applied to all the electrodes of the other group among the groups114.

Referring again to FIG. 2, the touch IC 130 applies the touch scansignal to the electrodes 112 through display driver IC 120, and thendetects the change in the capacitance of each electrode to determinewhether an electrode area is touched. The touch IC 130 and the displaydriver IC 120 are connected to each other through the touch IC channels,and the total number of touch IC channels is m/2. That is, in therelated art, the number of electrodes or lines is equal to the number oftouch IC channels, but in the present invention, the number of touch ICchannels decreases to a half of the number of electrodes 112 or lines113, which reduces the manufacturing cost and structure configuration.

Hereinafter, an electrode division method will now be described indetail with reference to FIGS. 4 to 8 according to an embodiment of thepresent invention. These methods can be implemented using the devices ofFIGS. 1-3 or other suitable display devices.

FIG. 4 is a diagram showing a first example of an electrode divisionmethod in a display device with an integrated touch screen according toan embodiment of the present invention.

As illustrated in FIG. 4, 160 electrodes can be divided into two groups,namely, an odd group and an even group. The odd group is connected tothe respective channels CH1 of the second switching units 126 in thedisplay driver IC 120, and the even group is connected to the respectivechannels CH2 of the second switching units 126. When the sync signalgenerator 122 generates the second sync signal “1” indicating the touchdriving mode and the switching control signal generator 123 generatesthe second control signal “01” designating the channel CH1, therespective channels CH1 of the second switching units 126 are connectedto the electrodes of the odd group. That is, all the channels CH1 ofeach of the second switching units 126 are connected to thecorresponding electrodes of the odd group. When the sync signalgenerator 122 generates the second sync signal “1” indicating the touchdriving mode and the switching control signal generator 123 generatesthe second control signal “10” designating the channel CH2, therespective channels CH2 of the second switching units 126 are connectedto the electrodes of the even group. Thus in the example of FIG. 4, theelectrodes 112 may be divided into groups having specificconfigurations.

FIGS. 5A to 5D are diagrams respectively showing experiment data oftouch sensitivity detected according to the method of FIG. 4.

In the present experiment data, the X axis indicates time, and the yaxis indicates raw count. A raw count value is a value that becomesfundamental for measuring touch sensing, and is to represent a touchsensing signal as a touch clock count value. A touch driving pulse isapplied selectively to the odd group and even group of electrodes shownin FIG. 4. Since the electrodes immediately neighboring the electrodenumbers 39 and 40 belong to the same even group, when the touch drivingpulse is applied to such electrodes, a high touch sensitivity isprovided. On the other hand, since some electrodes immediatelyneighboring the electrode numbers 51 and 66 belong to differentelectrode groups (i.e., the odd group), the neighboring electrodes aregrounded when the touch driving pulse is applied to the electrodes 51and 66. As a result, the touch sensitivity in such area is lower thanthe touch sensitivity around the electrode numbers 39 and 40. This canbe seen in FIGS. 5A and 5B. Referring to the experiment data, a rawcount difference of the electrode number 39 (highlighted in FIG. 4) is200, a raw count difference of the electrode number 40 is 230, a rawcount difference of the electrode number 51 is 100, and a raw countdifference of the electrode number 66 is 160. A large raw countdifference denotes that the touch sensitivity is better in proportionthereto. In the present experiment data, there are no electrodes (whichare connected to different channels of the second switching unit 126)respectively adjacent to the electrode number 39 and the electrodenumber 40, and thus, the raw count difference of each of the electrodenumber 39 and electrode number 40 is greater than that of each of theelectrode number 51 and electrode number 66, which means that the touchsensitivity in the area of the electrode numbers 39 and 40 is betterthan the touch sensitivity in the area of the electrode numbers 51 and66. Thus to enhance the touch sensitivity of the touch panel, it wouldbe desirable to minimize the number of adjacent electrodes that belongto a different group of touch electrodes driven at a different time.Accordingly, FIGS. 6 and 7 provide examples of dividing or grouping thetouch electrodes according to the present invention to maximize thetouch sensitivity of the display panel. FIGS. 6 and 7 illustrate theexamples of a group division method that enables the obtainment of hightouch sensitivity, based on the experiment data of FIG. 5. Asillustrated in FIGS. 6 and 7, a plurality of electrodes may be dividedinto a plurality of block type groups. For example, when the pixel areaof the panel 110 is rectangular in shape, by dividing the electrodes 112into a plurality of groups along a short (shorter) side direction tohave a rectangular shape, RC delay is reduced between the adjacentelectrodes included in different groups, thus increasing the touchsensitivity of the display device.

FIG. 6 is a diagram showing a second example of an electrode divisionmethod in the display device with the integrated touch screen accordingto an embodiment of the present invention.

Referring to FIG. 6, the plurality of electrodes 112 are divided intotwo block type groups 114 along the direction of the shorter side of thetouch screen 111. One (114 a) of the groups 114 is connected to thechannels CH1 of the second switching units 126 in the display driver IC120, and the other group 114 b is connected to the channels CH2 of thesecond switching units 126. When the sync signal generator 122 generatesthe second sync signal “1” indicating the touch driving mode and theswitching control signal generator 123 generates the second controlsignal “01” designating the channel CH1, the respective channels CH1 ofthe second switching units 126 are connected to all the electrodes ofthe one group 114 a. When the sync signal generator 122 generates thesecond sync signal “1” indicating the touch driving mode and theswitching control signal generator 123 generates the second controlsignal “10” designating the channel CH2, the respective channels CH2 ofthe second switching units 126 are connected to all the electrodes ofthe other group 114 b. In the present example, when the pixel area ofthe panel 110 is rectangular in shape, the block type groups 114 may beformed by dividing the electrodes 112 along a short/shorter sidedirection of the touch screen 111 to have a rectangular shape or thelike, and the numbers of electrodes in each of the divided groups may bethe same. As in the present embodiment, by dividing the electrodes intoa plurality of groups along a short/shorter side direction of the touchscreen 111 to have a rectangular shape or the like, a proximal surfacebetween the groups 114 is minimized and thus, a potential differencebetween the electrodes 112 connected to the respective channels of thedifferent second switching units 126 is minimized, thereby increasingthe touch sensitivity of the panel 110. In the above-described example,the pixel area is the same area as that of the touch screen 111.

FIG. 7 is a diagram showing a third example of an electrode divisionmethod in the display device with the integrated touch screen accordingto an embodiment of the present invention.

Referring to FIG. 7, the electrodes 112 are divided into three blocktype groups 114 (114 a, 114 b, 114 c), and if the pixel area of thepanel 110 is rectangular in shape, similarly to the example of FIG. 6,the block type groups 114 may be formed by dividing the electrodes 112into a plurality of groups along a short/shorter side direction of thetouch screen 111 to have a rectangular shape or the like. In this way,by dividing the electrodes 112 into the plurality of groups 114 a, 114b, 114 c along the short side direction to have the rectangular or othershape, a proximal surface between the groups 114 is minimized and thus,a potential difference between the electrodes 112 connected to therespective channels of the different second switching units 126 isminimized, thereby increasing the touch sensitivity of the touch screen111. The detailed description of this example is the same as that of theabove-described second example, and thus is not provided.

In the example of FIG. 7, because there exist three groups 114 a, 114 band 114 c of the electrodes 112, each of the second switching units 126would have one input and three outputs CH1, CH2 and CH3 whichrespectively control the three groups 114 a, 114 b and 114 c. As such,the number of second switching units 126 needed may correspond to m/n.In this regard, the switching control signal generator 123 is configuredto output appropriate control signals so that each of the groups 114 a,114 b and 114 c is selectively and independently driven by controllingthe output selection among the outputs CH1, CH2 and CH3. Theconfiguration of the first switching units 125 would be the same as thatshown in FIGS. 2 and 3. Thus, depending on the number of groups ofelectrodes formed, the corresponding same number of touch channels foreach of the second switching units 126 may be used.

According to the present embodiments, a plurality of electrodes havebeen exemplarily described as being divided into two groups or threegroups, but may be divided into four or more groups according to thenumber of electrodes.

A driving method of the display device with the integrated touch screenhaving the above-described configuration, according to an embodiment ofthe present invention, will be described in detail with reference toFIG. 2.

When the driving mode of the display device with the integrated touchscreen according to an embodiment of the present invention is in thedisplay driving mode, the sync signal generator 122 generates the firstsync signal “0” to transfer the first sync signal “0” to the firstswitching units 125, and the switching control signal generator 123generates the first control signal “00” to transfer the first controlsignal “00” to the second switching units 126.

The first switching units 125 are switched and connect the commonvoltage generator 121 to the second switching units 126, according tothe first sync signal “0”. The second switching units 126 are switchedand connect the m electrodes to the channels CH1 and CH2, according tothe first control signal “00”.

The common voltage generated by the common voltage generator 121 isapplied simultaneously to all the m electrodes 112 through the firstswitching units 125 and the second switching units 126.

When the driving mode of the display device is in the touch drivingmode, the sync signal generator 122 generates the second sync signal “1”to transfer the second sync signal “1” to the first switching units 125,and the switching control signal generator 123 generates the secondcontrol signal “01” or “10” to transfer the second control signal “01”or “10” to the second switching units 126.

The first switching units 125 are switched and connect the touch IC 130to the second switching units 126, according to the second sync signal“1”. The second switching units 126 are switched and connect one of thetwo groups 114 to the channels CH1 and CH2, according to the secondcontrol signal “01” or “10”. When the second control signal is “01”, thechannels CH1 of the second switching units 126 are connected to theelectrodes of one of the two groups 114. When the second control signalis “10”, the channels CH2 of the second switching units 126 areconnected to the electrodes (which are not connected to the channelsCH1) of the other group among the two groups 114.

The touch scan signal generated from the touch IC 130 is appliedsequentially to the two groups through the first switching units 125 andthe second switching units 126.

Some of the advantages associated with the above-described displaydevice with the integrated touch screen according to an embodiment ofthe present invention will now be provided.

In the present invention, by applying the common voltage or the touchscan signal to the electrodes of each group through the switching unitthat is connected to at least two or more electrode groups of theself-capacitive touch screen, the number of touch ICs and the number oftouch IC channels can be reduced which in turn reduces the manufacturingcost of the display device.

Furthermore, in the present invention, the common voltage Vcom isapplied directly from the display driver IC to the electrodes withoutbeing applied to the electrodes through the touch IC, and thus, imagequality can be prevented from being degraded.

According to the embodiments of the present invention, the switchingunit is connected to at least two or more electrode groups of theself-capacitive touch screen, and the common voltage or the touch scansignal is applied to the electrodes of each group through the switchingunit, thus reducing the number of touch ICs and the number of touch ICchannels which in turn reduces the manufacturing cost of the displaydevice.

Moreover, according to the embodiments of the present invention, thecommon voltage is not applied to the electrodes though the touch IC, butthe common voltage is applied directly from the display driver IC to theelectrodes, thus preventing image quality from being degraded.

Moreover, according to the embodiments of the present invention, theplurality of electrodes are divided into the plurality of groups, andinter-electrode RC delay is reduced by minimizing a proximal surfacebetween the electrode groups, thus enabling more accurate touch sensing.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A driver circuit for driving a self-capacitivetouch sensitive display device comprising a two dimensional array oftouch electrodes that represent all touch electrodes of the displaydevice used for determining touch with self-capacitive touch sensing,the touch electrodes including at least a first group of touchelectrodes including two or more first touch electrodes and a secondgroup of touch electrodes including two or more second touch electrodesdifferent from the first touch electrodes, the driver circuitcomprising: a first circuit to generate a touch scan signal forself-capacitive touch sensing; and a second circuit to: provide a commonvoltage to both the first group of touch electrodes and the second groupof touch electrodes during a display drive period via a plurality oflines, provide the touch scan signal to the two or more first touchelectrodes of the first group of touch electrodes simultaneously duringa first part of a touch drive period for self-capacitive touch sensing;and provide the touch scan signal to the two or more second touchelectrodes of the second group of touch electrodes simultaneously duringa second part of the touch drive period for self-capacitive touchsensing, the second circuit providing the touch scan signal in saidtouch drive period to each of the touch electrodes that represent alltouch electrodes of the display device used for determining touch withself-capacitive touch sensing, the second circuit providing the touchscan signal for self-capacitive touch sensing via the plurality oflines, and wherein each corresponding line is electrically connected toa single corresponding touch electrode.
 2. The driver circuit of claim1, wherein the second circuit provides the touch scan signal to each ofthe touch electrodes of the display device that are used for determiningtouch once in said touch drive period.
 3. The driver circuit of claim 1,wherein the second circuit provides the touch scan signal to the firstgroup of touch electrodes and to the second group of touch electrodessequentially.
 4. The driver circuit of claim 1, wherein the touchelectrodes are arranged in a rectangular shape including at least afirst edge and a second edge that is shorter than the first edge, thetouch electrodes being divided into the first group of touch electrodesand the second group of touch electrodes along the second edge.
 5. Thedriver circuit of claim 1, wherein: during the display drive period,each of the touch electrodes operates as a common electrode fordisplaying images on the display device, and during the touch driveperiod, each of the touch electrodes operates as a touch electrode tosense a touch input.
 6. The driver circuit of claim 1, wherein thesecond circuit comprises: a common voltage generator configured togenerate the common voltage; a sync signal generator configured togenerate a sync signal indicating the display drive period and the touchdrive period; a switching control signal generator configured togenerate a control signal which allows the touch electrodes to besimultaneously connected to the common voltage generator during thedisplay drive period, or allows the first group of touch electrodes orthe second group of touch electrodes to be connected to the firstcircuit during the touch drive period, according to the sync signal; anda plurality of switches configured to operate according to the syncsignal and the control signal.
 7. The driver circuit of claim 6, whereinthe switches include: first switches connected to the common voltagegenerator and the first circuit, and second switches connected to thefirst switches and the first and second groups of touch electrodes. 8.The driver circuit of claim 7, wherein: when the sync signal is a firstsync signal indicating the display drive period, the first switcheselectrically connect the common voltage generator to the secondswitches, and when the sync signal is a second sync signal indicatingthe touch drive period, the first switches electrically connect thefirst circuit to the second switches.
 9. The driver circuit of claim 8,wherein: when the control signal is a first control signal correspondingto the first sync signal indicating the display drive period, the secondswitches electrically connect the touch electrodes to the firstswitches, and when the control signal is a second control signalcorresponding to the second sync signal indicating the touch driveperiod, the second switches electrically connect the first group oftouch electrodes or the second group of touch electrodes to the firstswitches.
 10. A touch sensitive display device comprising: a twodimensional array of touch electrodes that represent all touchelectrodes of the display device used for determining touch withself-capacitive touch sensing, the touch electrodes including at least afirst group of touch electrodes including two or more first touchelectrodes and a second group of touch electrodes including two or moresecond touch electrodes different from the first touch electrodes; and adriver circuit, including: a first circuit to generate a touch scansignal for self-capacitive touch sensing; and a second circuit toprovide a common voltage to both the first group of touch electrodes andthe second group of touch electrodes during a display drive period via aplurality of lines, to provide the touch scan signal to the two or morefirst touch electrodes of the first group of touch electrodessimultaneously during a first part of a touch drive period forself-capacitive touch sensing, and to provide the touch scan signal tothe two or more second touch electrodes of the second group of touchelectrodes simultaneously during a second part of the touch drive periodfor self-capacitive touch sensing, the second circuit providing thetouch scan signal in said touch drive period to each of the touchelectrodes that represent all touch electrodes of the display deviceused for determining touch with self-capacitive touch sensing, thesecond circuit providing the touch scan signal for self-capacitive touchsensing via the plurality of lines, and wherein each corresponding lineis electrically connected to a single corresponding touch electrode. 11.The display device of claim 10, wherein the second circuit provides thetouch scan signal to each of the touch electrodes of the display devicethat are used for determining touch once in said touch drive period. 12.The display device of claim 10, wherein the second circuit provides thetouch scan signal to the first group of touch electrodes and to thesecond group of touch electrodes sequentially.
 13. The display device ofclaim 10, wherein the touch electrodes are arranged in a rectangularshape including at least a first edge and a second edge that is shorterthan the first edge, the touch electrodes being divided into the firstgroup of touch electrodes and the second group of touch electrodes alongthe second edge.
 14. The display device of claim 10, wherein: during thedisplay drive period, each of the touch electrodes operates as a touchelectrode for displaying images on the display device, and during thetouch drive period, each of the touch electrodes operates as a touchelectrode to sense a touch input.
 15. The display device of claim 10,wherein the second circuit comprises: a common voltage generatorconfigured to generate the touch voltage; a sync signal generatorconfigured to generate a sync signal indicating the display drive periodand the touch drive period; a switching control signal generatorconfigured to generate a control signal which allows the touchelectrodes to be simultaneously connected to the common voltagegenerator during the display drive period, or allows the first group oftouch electrodes or the second group of touch electrodes to be connectedto the first circuit during the touch drive period, according to thesync signal; and a plurality of switches configured to operate accordingto the sync signal and the control signal.
 16. The display device ofclaim 15, wherein the switches include: first switches directlyconnected to the common voltage generator and the first circuit, andsecond switches connected to the first switches and the first and secondgroups of touch electrodes.
 17. The display device of claim 16, wherein:when the sync signal is a first sync signal indicating the display driveperiod, the first switches electrically connect the common voltagegenerator to the second switches, and when the sync signal is a secondsync signal indicating the touch drive period, the first switcheselectrically connect the first circuit to the second switches.
 18. Thedisplay device of claim 17, wherein: when the control signal is a firstcontrol signal corresponding to the first sync signal indicating thedisplay drive period, the second switches electrically connect the touchelectrodes to the first switches, and when the control signal is asecond control signal corresponding to the second sync signal indicatingthe touch drive period, the second switches electrically connect thefirst group of touch electrodes or the second group of touch electrodesto the first switches.
 19. A method for driving a touch sensitivedisplay device comprising a two dimensional array of touch electrodesthat represent all touch electrodes of the display device used fordetermining touch with self-capacitive touch sensing, the touchelectrodes including at least a first group of touch electrodesincluding two or more first touch electrodes and a second group of touchelectrodes including two or more second touch electrodes different fromthe first touch electrodes, the method comprising: generating a touchscan signal for self-capacitive touch sensing; providing a commonvoltage to both the first group of touch electrodes and the second groupof touch electrodes during a display drive period via a plurality oflines; providing the touch scan signal to the two or more first touchelectrodes of the first group of touch electrodes simultaneously duringa first part of a touch drive period for self-capacitive touch sensing;and providing the touch scan signal to the two or more second touchelectrodes of the second group of electrodes simultaneously during asecond part of the touch drive period for self-capacitive touch sensing,the touch scan signal provided in said touch drive period to each of thetouch electrodes that represent all touch electrodes of the displaydevice used for determining touch in said touch drive period withself-capacitive touch sensing, the touch scan signal for self-capacitivetouch sensing provided via the plurality of lines, wherein eachcorresponding line is electrically connected to a single correspondingtouch electrode.
 20. The method of claim 19, wherein the touch scansignal is provided to each of the touch electrodes of the display devicethat are used for determining touch once in said touch drive period. 21.The method of claim 19, wherein the touch scan signal is provided to thefirst group of touch electrodes and to the second group of touchelectrodes sequentially.
 22. The method of claim 19, wherein the touchelectrodes are arranged in a rectangular shape including at least afirst edge and a second edge that is shorter than the first edge, thetouch electrodes being divided into the first group of touch electrodesand the second group of touch electrodes along the second edge.
 23. Themethod of claim 19, wherein: during the display drive period, each ofthe touch electrodes operates as a common electrode for displayingimages on the display device, and during the touch drive period, each ofthe touch electrodes operates as a touch electrode to sense a touchinput.
 24. The method of claim 19, further comprising: generating a syncsignal indicating the display drive period and the touch drive period;and generating a control signal which allows the touch electrodes to besimultaneously connected to the common voltage during the display driveperiod, or allows the first group of touch electrodes or the secondgroup of touch electrodes to be connected to the touch scan signalduring the touch drive period, according to the sync signal.
 25. Thedisplay device of claim 10, wherein the first group of touch electrodesis not overlapped with the second group of touch electrodes.
 26. Thedriver circuit of claim 1, wherein the touch electrodes further comprisea third group of touch electrodes including two or more third touchelectrodes, wherein the second circuit provides the common voltage tothe third group of touch electrodes during the display drive period, andprovides the touch scan signal to the two or more third touch electrodesof the third group of touch electrodes simultaneously during a thirdpart of the touch drive period.
 27. The display device of claim 10,wherein the touch electrodes further comprise a third group of touchelectrodes including two or more third touch electrodes, wherein thesecond circuit provides the common voltage to the third group of touchelectrodes during the display drive period, and provides the touch scansignal to the two or more third touch electrodes of the third group oftouch electrodes simultaneously during a third part of the touch driveperiod.
 28. The method of claim 19, wherein the touch electrodes furthercomprise a third group of touch electrodes including two or more thirdtouch electrodes, and the method further comprises: providing the commonvoltage to the third group of touch electrodes during the display driveperiod, and providing the touch scan signal to the two or more thirdtouch electrodes of the third group of touch electrodes simultaneouslyduring a third part of the touch drive period.
 29. A touch sensitivedisplay device comprising: a display panel comprising: a plurality oftouch electrodes, the plurality of touch electrodes including at least afirst group of touch electrodes including a first touch electrode and asecond touch electrode and a second group of touch electrodes includinga third touch electrode and a fourth touch electrode, and a plurality oftouch lines, the plurality of touch lines including at least a firsttouch line, a second touch line, a third touch line and a fourth touchline; and a display driver Integrated Circuit (IC) comprising aplurality of touch channel outputs, the plurality of touch channeloutputs including at least a first touch channel output, a second touchchannel output, a third touch channel output and a forth touch channeloutput; wherein the first touch electrode is not overlapped with thesecond touch electrode in the first touch electrode group of the touchelectrodes, and the third touch electrode is not overlapped with thefourth touch electrode in the second touch electrode group of the touchelectrodes, wherein the first touch electrode is connected to the firstchannel output via the first touch line, the second touch electrode isconnected to the second channel output via the second touch line, thethird touch electrode is connected to the third channel output via thethird touch line, the forth touch electrode is connected to the fourthchannel output via the fourth touch line, wherein the display driver ICis configured to supply a common voltage to the plurality of touchelectrodes and drive a data line of the display panel during a displayperiod, wherein the display driver IC is configured to supply a touchscan signal to the plurality of touch electrodes during a touch period,wherein the display driver IC is configured to supply the touch scansignal to the first touch electrode and the second touch electrodesimultaneously during a first part of the touch period, and wherein thedisplay driver IC is configured to supply the touch scan signal to thethird touch electrode and the fourth touch electrode simultaneouslyduring a second part of the touch period.